Question

Lars wants to know if warming up will help runners sprint faster. Twenty-four track and field athletes volunteered to participate in his study. He randomly assigns 12 athletes to warm-up for 10 minutes. All 24 participants sprint the same distance. He calculates the mean for each group and determines that the mean for the warm-up group was 7.8 seconds and the mean for the other group was 9.8 seconds. To test the difference of means, he re-randomized the data 54 times, and the differences are plotted in the dot plot below. What can Lars conclude from her study?
A dot plot is shown labeled from negative 2.5 to positive 2. Above the negative 2.5 are 3 dots. Above the negative 2 are 6 dots. Above the negative 1.5 are 9 dots. Above the negative 1 are 12 dots. Above the negative 0.5 are 6 dots. Above the 0.0 are 4 dots. Above the 0.5 are 3 dots. Above the 1.0 are 7 dots. Above the 1.5 are 3 dots. Above the 2.0 is 1 dot.

Answers
The difference in the means is significant because a difference of 2 is very likely.
The difference in the means is significant because a difference of 2 is not very likely.
The difference in the means is not significant because a difference of 2 is not very likely.
The difference in the means is not significant because a difference of 2 is very likely.

Answer 1

The answer is A its very likely and its very significant.

Answer 2

The answer is B: The difference in the means is significant because a difference of 2 is not very likely.